II. International Law as a Potential Threat to Liberty

Legal rules affect liberty in at least two ways. Rules may contribute to the establishment of a reasonably secure political, social, cultural, and economic order that provides a foundation for voluntary interactions and personal flourishing. The concept of “ordered liberty” captures this first function. In addition, rules can restrict the choices made within the framework of ordered liberty. A rule forbidding murder falls into the first category, while one punishing criticism of political authority falls into the second. In normative terms, first-category rules advance the values embedded in liberty, while second-category rules restrict liberty. Categorization depends heavily on context, rather than on a priori principles.

For rules to function in either way, however, some mechanism must exist to induce compliance. In municipal law, the state's coercive power (where it exists) supplies the most obvious means of enforcement, either directly or as a background threat. Other pathways to compliance include informal social sanctions. More problematically, some theorists also believe in a process of rule internalization, through which individuals impose psychic costs on themselves for rule transgressions and psychic rewards for rule compliance.¹⁴

International law as conventionally conceived seems to exclude all means of inducing compliance save informal social sanctions. The international community, as opposed to individual states, supposedly lacks coercive power, and societies ex definitio lack interior lives and psychic states.¹⁵

Accordingly, the compliance literature for the most part concentrates on how reputation and retaliation serve to induce states to observe international law.¹⁶

More recently, however, scholars have identified ways in which international law can have directly coercive effect. International tribunals can issue monetary or punitive judgments that states perceive as having direct effect and therefore uncritically implement. Domestic tribunals can apply international rules in a self-perceived capacity of agent for the international lawmaker.¹⁷

To be sure, these examples rest ultimately on the willingness of national governments and other actors to fulfill their roles in administering coercive sanctions. But this reservation is also true of municipal law, which depends fundamentally on the willingness of individuals to play their part in the execution of the law.

Moreover, most legal academics seem to favor extending the coercive power and reach of international law. To take just one prominent example, the International Criminal Court (ICC) has generated a cottage industry of largely celebratory work, even though it has yet to take on its first case.¹⁸

The ICC, which came into being in 2002, represents a culmination of decades of work, led by the United States, to establish a permanent international body to investigate and prosecute human rights violations arising out of political and social catastrophes. Previously, the United Nations Security Council had established tribunals on an ad hoc basis to deal with particular disasters. The United States ultimately opposed the final version of the Rome Statute, which created the ICC, because it allows the ICC's prosecutor and judges to decide on their own whether to act, rather than awaiting referral of a case from the Security Council (the practice with the ad hoc tribunals). Professors of international law mostly have deplored the U.S. position. More generally, the U.S. professoriat, by numbers and stature, overwhelmingly favors the exercise of judicial power, both international and domestic, to punish violations of international law; and Commonwealth and European scholars seem largely to envy, on behalf of their national courts, the power that U.S. judges wield. Thus, even if at present the coercive, and potentially liberty-threatening, dimensions of international lawmaking seem marginal, the weight of opinion would wish this lawmaking to acquire great instrumental power.

Accordingly, without exaggerating the practical significance of the issue, we can regard some instances of international lawmaking as coercive and therefore a potential threat to liberty. Individuals have been jailed (and in the case of the post–World War II proceedings, hanged) as a result of the decisions of international criminal courts, and a permanent body to carry out the prosecution and punishment of international crimes now exists. Litigants have used domestic courts to sue individuals and firms for large sums because of purported violations of international law. Business regulation increasingly turns on the decisions of international bodies. The enforceability and interpretation of a widening range of contracts turns on the meaning of international law. Each of these instances contains the potential of arbitrary encroachments on liberty.

By no means do I wish to suggest that all international lawmaking is presumptively a threat to liberty, much less that it does not contribute to the ordering of liberty necessary for human flourishing and freedom. Coercion brought against, for example, persons guilty of torture and murder does not set off many alarm bells. The point, rather, is that whenever enactment of a law creates the possibility of coercion, one legitimately can ask whether the processes involved in its enactment contain at least minimal safeguards to discourage the arbitrary exercise of power.

I also concede that whether given procedures satisfy process values depends on context, and that the contexts of international lawmaking differ in many respects from the context of domestic lawmaking. Because there is no such thing as an international government per se, clear separation of powers, much less elaborate checks and balances, is hard to construct. Because direct election of legislators is virtually absent (the European Parliament providing the only counterexample, and that a qualified one), the problem of lawmaker accountability necessarily involves agency questions.¹⁹

In some instances, the power of national states to reject rules of international law substitutes for separation of powers and checks and balances, but, as I observed above, this mechanism does not always work.

My point, in sum, is that some international rules can be sufficiently coercive to justify an inquiry into the suitability of the lawmaking processes that generated these rules. What constitutes a minimally acceptable lawmaking process is a difficult question, and a simple analogy to domestic lawmaking is an insufficient response. But the growing presence of international rules in contemporary life, and the ambitions of some for an even greater role for these rules, invites an inquiry into the legitimacy of their genesis, interpretation, and application.

III. International Institutions as a Potential Threat to Liberty

Imagine a treaty under which several states agree to establish an international agency invested with the authority to issue binding pronouncements regarding some set of topics. To make the problem more interesting, imagine that the treaty posits that the agency's determinations about its authority to issue particular pronouncements cannot be challenged in national courts. Further imagine that the treaty obligates each signatory to implement the agency's determinations, and in particular to give them “the full force of law.”

This lawmaking structure is far from hypothetical. Substitute “Constitution” for “treaty” and “Supreme Court of the United States” for “international agency” and we have the structure of U.S. constitutional law (albeit due to evolved understandings rather than because of the written text of the document).²⁰

The 1957 Treaty of Rome constitutes the European Court of Justice in similar fashion, and the 1950 European Convention on Human Rights does much the same for the European Court of Human Rights. The 1945 Articles of Agreement of the International Monetary Fund and the International Bank for Reconstruction and Development (better known as the World Bank) arrogate an adjudicatory function for the respective executive bodies of these institutions. The 1998 Rome Statute for the International Criminal Court puts that court in the position of resolving a number of issues involving the scope and meaning of international criminal law.²¹

Consider in particular what kinds of questions the International Criminal Court must address, how it must address them, and the consequences of its choices. The Rome Statute authorizes punishment of four generic crimes—genocide, crimes against humanity, war crimes, and aggression. The last category is contingent on the later adoption of a definition of that class of crimes, because the authors of the statute concluded that the concept of aggression at present lacks sufficient clarity and acceptance to support prosecutions. The statute's definitions of the three crimes currently proscribed contain many illustrations, but each rests ultimately on stated general principles that invite elaboration and expansion. To take just one of these proscribed acts, a “crime against humanity” entails imprisonment “in violation of the fundamental rules of international law” without further specification, in addition to “persecution” on the basis of, inter alia, politics or ethnic, cultural, or religious differences. But what norm constitutes a “fundamental” rule of international law? What acts amount to “persecution”? How are we to determine the causal links between persecution and difference? These are questions of critical importance that only organs of the ICC can resolve.²²

Much the same goes for other important questions, such as the existence of excuses or justifications for otherwise criminal behavior.²³ Finally, in every particular case, the court must determine either that no state with jurisdiction over an offense is conducting an investigation, or that states that have conducted or are conducting an investigation are unable or unwilling “genuinely” to act.²⁴

It is exactly the process by which the prosecutor and the court must make these fundamental substantive choices that is troubling. Under the terms of the Rome Statute, the prosecutor and the court act hermetically. Each must convince itself of the plausibility of its interpretations, and the court may refuse to accept the prosecutor's determinations. But no outside body can override these decisions. By the terms of article 16 of the statute, the United Nations Security Council may order a one-year delay of an investigation or prosecution, but such action would require the consent of all five permanent members of the Security Council and in any event would not be conclusive.

In effect, then, the prosecutor and the judges—each subject to no outside review once selected for a nonrenewable nine-year term—have the power to decide whether individual states have “genuinely” pursued an offense, whether particular conduct constitutes an offense, and what constitutes an acceptable excuse or justification for conduct otherwise constituting an offense. They must make these determinations in the face of scanty precedent or historical background, and in contexts that often implicate deep geopolitical antagonisms. They do have access to a burgeoning body of scholarly advice about how they should go about their work, but this, as scholarship typically does, contains as many points of view as there are authors. At bottom, only such internal constraints rooted in the construction of professional identities as these actors might possess (if any) constrain their exercise of significant coercive power.

What the Europeans call the Luxembourg and Strasbourg courts—the EC's European Court of Justice (in Luxembourg) and the Council of Europe's European Court of Human Rights (in Strasbourg)—present similar issues. At the same time, some differences between these bodies, and between them and the ICC, are apparent. Although the Luxembourg court has final say on the interpretation of the Treaty of Rome (the foundational instrument of the European Community), the existence of a separate EC lawmaking process complicates and to some extent confounds the court's freedom of action. Moreover, the court's jurisdiction does not extend beyond the twenty-five members of the EC. Finally, even though the court's decrees are said to have direct effect, they have practical significance only to the extent that national governments comply with them. The Luxembourg court has evinced a fairly high degree of tolerance for foot-dragging and circumvention, suggesting that less coercion attends its edicts than one might assume. Finally, the Luxembourg court has carried on in various forms for fifty years, creating a history that provides an additional layer of constraint.

The Strasbourg court is nested in a different institutional structure. It has functioned in one capacity or another since 1959, but only since 1998 have all persons with human rights claims against the forty-four states bound by the European Convention enjoyed an unqualified right to file suit.²⁵

Due at least in part to this structural change, the twenty-first century has seen a remarkable increase in the number of the court's controversial decisions, such as those concerning the rights of sexual minorities, the right to die, and the procedures for conducting police investigations.²⁶ The Strasbourg court faces no counterpart legislative or executive organs, unlike the Luxembourg court. Moreover, the Strasbourg court's ability to enforce its decisions through fines operates fairly automatically, limiting the power of intransigent states to undermine its judgments.²⁷

I discuss these bodies because they present the most straightforward instances of delegation of coercive lawmaking power to an international body. Other instances of potentially greater significance exist. Under legal theories that enjoy wide circulation in the academic community and modest support in some domestic courts, various international bureaucracies, such as the United Nations Human Rights Commission and the International Committee of the Red Cross, enjoy a more diffuse power to create “customary international law,” which some courts regard as binding. Were this theory to gain widespread credence, many international bodies would take on the role of coercive lawmakers.

For two reasons, however, I defer discussion of these bodies to the next section. First, at present the claims for their lawmaking capacity are outliers rather than mainstream legal doctrine. Second, their actions take on the nature of customary international law only if courts reach this conclusion. The legitimacy of this process thus is part of a broader inquiry about domestic common law methods as means of international lawmaking.

Are the constraints that currently operate on the International Criminal Court, the European Court of Justice, and the European Court of Human Rights sufficient to protect against arbitrary restrictions of liberty? One possible response is that every constitutional court, most particularly the Supreme Court of the United States, functions in this manner, and most people consider the development and empowerment of these institutions a good thing. Why shouldn't these international courts work as well as these national courts do?

The most obvious rejoinder is that international organs are different from national courts. To begin with, they draw on agents from different states with various cultures, historical experiences, and professional identities. They confront a greater range of contested issues than do most bodies, and they do so without the benefit of an unstated cultural consensus or broad historical memory. Yes, most institutions may go through a period of foundational angst, during which the absence of a developed institutional culture or guidance from precedent may complicate choices about appropriate actions. But the international organs present an aggravated case. The Supreme Court of the United States, for instance, enjoyed the benefit of its justices' common grounding in British common law, a frame of reference that they shared with virtually all lawyers of their day. Nothing similar binds the ICC or the Strasbourg or Luxembourg courts.

The absence of cultural and historical constraints might not matter as much if these organs largely engaged in technocratic exercises to reach important but obscure results. One could imagine an international tribunal that, for example, settled disputes over the ownership of particular locations on the radio spectrum based exclusively on issues of engineering and simple rules of allocational priority. Interestingly, the real-world analog to this hypothetical organ—the dispute resolution services of the Internet Corporation for Assigned Names and Numbers (ICANN), which deals with ownership of internet domain names—does not purport to bind national legal systems, which remain free to reject ICANN outcomes.²⁸

An analogous process, the settlement of investment disputes by international arbitration, has generated heated criticism exactly for its narrow focus on property rights at the expense of other values.²⁹ The mandates of the ICC and the Luxembourg and Strasbourg courts go far beyond technocratic problems, however. They extend to deep and culturally divisive issues such as the duty to refuse an illegitimate order, the role of amnesty and reconciliation in the wake of conflict, the balance between press freedom and protection of individual reputation and group sensitivities, and the rights, powers, and immunities of members of marginalized groups.

There is a point of view that maintains that institutions not subject to conventional democratic constraints ought to resolve emotionally charged and divisive issues, because democracy breaks down under stress. According to this argument, resolution of fundamental problems requires reasoned deliberation, which a society awash in passion cannot sustain. In lieu of neglecting these problems, a nation can turn to disinterested decision makers operating behind a cloak of moral authority.³⁰

For proponents of this argument, a different system of checks must apply to such tribunals. Rather than submitting their decisions to formal institutional constraints, the wielders of this power instead must display due regard for the limits of their moral authority. This intangible constraint, in turn, implicates an alliance between the tribunal and its commentators, as the weight of scholarly opinion presumably can bolster or reduce the authority behind a controversial decision.

Even as applied to a well-entrenched and successful institution such as the Supreme Court of the United States, this argument invites considerable skepticism. Whatever the particular endowments of the Supreme Court justices, their collective ability to sense the intangible limits on their authority is impaired by the cloistered lives that their institutional roles impose on them. Institutional checks on an organ's lawmaking powers exist precisely because individual judgment and discretion are not always sufficient to prevent great blunders. The history of the Supreme Court's more ambitious constitutional decision making—the infamous Dred Scott decision, only the second occasion on which the Court struck down a federal statute, comes to mind³¹

—suggests why something more than intuitive self-restraint may be necessary.³²

An extension of the democracy-breakdown argument to an international tribunal seems especially implausible. The idea that such institutions from their inception will wield sufficient moral authority to overcome deep conflict strikes me as wishful thinking. The probability that jurists from different nations can build coalitions that withstand local passions and entrenched political opposition veers toward nil. More likely is the rise of perceptions that particular decisions represent national prejudice. The prosecution of Slobodan Milosevic by the UN's special court for the former Yugoslavia (a precursor of the ICC) appears to have united Serbs in a conviction that the rest of Europe hates them, rather than leading them to the realization that their former leader had disgraced their nation with his policies. Conflicts between the British House of Lords and the Strasbourg court give the impression that a controlling majority of the human rights tribunal has thrown its lot in with a Franco-German cabal intent on undermining traditional underpinnings of British liberty in favor of a continental conception of social-democratic dirigisme.³³

The point is not that in either case these fears are well founded, but rather that they exist and may become more powerful with the growth and development of international tribunals.

One might sensibly respond that all international organs, the ICC and the Luxembourg and Strasbourg courts included, operate under one basic constraint, namely the process for choosing their members. A selection process that allows for state dissent, combined with limited terms for the persons selected, sets up an ex ante check on what an organ can do. States may miscalculate what a judge will do once seated—the United States has some familiarity with this problem—but, with some delay, they can correct for that.

In some instances where discretion is concentrated in a single person, such as the prosecutor of the ICC, the selection power, or more precisely the power not to reappoint, may serve as a check on the actor. In other cases, the selection power may deter extreme deviations from an organ's stated responsibilities. Often, however, the structure of selection of members of these organs militates against discipline. The common practice of international tribunals, including the ICC and the Luxembourg and Strasbourg courts, entails allocating positions to individual states or cohesive blocs of states. As a result, stable coalitions can form to marginalize persons selected by dissident states. In the case of the ICC, for example, a single judge selected by the United States could not defeat a coalition of states hostile to U.S. exercises of power, a scenario that is far from hypothetical.³⁴

I do not mean to suggest that any of these tribunals face an insurmountable hurdle. It is not inconceivable that the ICC, for example, might simultaneously avoid taking on any deeply controversial cases while dealing with those obvious outrages that occur. Perhaps, over a decade or more, the leadership of the court might acquire a reputation for balanced action and careful exercise of its powers, thereby accruing moral authority and general respect. But this would take luck as well as prudence. Were a conflict to arise that pitted great powers against each other or otherwise seriously divided world opinion, the tribunal would find it exceedingly hard to seem neither partisan nor toothless.

In the case of the ICC, the risks seem especially unnecessary. An obvious model of easily imposed institutional checks existed at the time of the adoption of the Rome Statute. Since the creation of the United Nations, all war crimes tribunals depended on authorization by the Security Council, a body that acts only in the absence of the disapproval of any of the five traditional nuclear powers.³⁵

In the past, each opportunity for international intervention in the face of domestic inability to redress gross misconduct depended on the existence of the level of consensus that Security Council action entails. Requiring the ICC to await a Security Council resolution before taking jurisdiction over any particular conflict—the position for which the United States continues to hold out, and the reason for its refusal to ratify the 1998 Rome Statute—would have preserved this institutional structure.

In the abstract, one might see a contradiction between the creation of an institution intended to bring the most terrible kinds of crimes to justice and the retention of a great-power veto over its actions. This objection, however, rests on confusion of the two bases of the ICC's jurisdiction. Credible allegations of the commission of an international crime, one should recall, by themselves are insufficient to justify action by the ICC. The ICC also must determine that no state possesses the capacity and desire to engage in a “genuine” effort to prosecute. Its jurisdiction, in other words, depends fundamentally on a determination that state-level action has failed. This latter consideration, unlike the determination of the existence of the elements of a crime, rests on irreducibly political and contestable considerations.

The Security Council is an appropriate body to make judgments about national incapacity to prosecute international crimes. Expecting a freestanding international institution to go after superpowers seems bizarre. In no other area touching on fundamental interests of a great power do we expect the United Nations to impose its will. It is not excessively cynical to believe that the proponents of the ICC who rejected the U.S. position did so largely out of a conviction that the threat to act against great powers would be empty, but that its hollowness would go unnoticed in at least some quarters.

I see nothing objectionable in general about a great-power veto over certain kinds of UN actions. One can embrace the concept of fundamental equality of all people without extending it to states: the United Nations since its inception has embraced the principle that some states are more equal than others. Each great power can prevent the United Nations from authorizing sanctions against itself or its clients. Allowing great powers also to have a veto over capacity-to-prosecute determinations seems a natural extension of the present structure of the international order.

The Strasbourg court represents a different set of institutional problems. On the one hand, the Council of Europe has no counterpart to the UN's Security Council: there is no club of regional powers that possesses a veto over actions undertaken on behalf of the Council of Europe. Constraining the court's mandate, itself only recently unleashed, thus would involve the construction of a new institution. On the other hand, the court's coercive power, although real enough, is less than that of a comparable common law court. In particular, it lacks the power to nullify laws or practices of which it disapproves or to order nonmonetary punishment for persons who disobey its mandates. Individual states thus can resist its orders at the cost of the payment of fines. Sufficient resistance, in turn, might deter the court from undertaking more challenging projects.

My broader point does not concern the particular value of the ICC, the Strasbourg court, or similar institutions. Rather, I wish to respond to the tendency of many scholars to see these organs as the wave of the future.³⁶

Judicial bodies no less than other instruments of state power can flourish under conditions of limited power. As more international organs acquire self-executing powers that can operate without substantial state cooperation, greater effort will be required to devise checks other than withdrawal of state consent. The current imbroglio over the refusal of the U.S. to recognize the ICC sheds some light on potential alternatives as well as illustrating the politics of institutional maximalism.

IV. Domestic Enforcement of International Law as a Potential Threat to Liberty

Different checking problems arise when independent national courts create, interpret, and impose international law. The problems are subtle, because the means of judicial lawmaking vary among systems and the uses of international law vary from analogy to direct authority. National courts also may differ in what sources and methods they use to ascertain what constitutes international law. Each of these factors can complicate the question of whether international lawmaking by national courts presents distinctive issues of accountability and constraint.

One important difference between national and international courts is that international institutions have acquired coercive powers relatively recently, and the most interesting and possibly worrisome cases involve proposals for future powers. As a result, institutional-design issues remain central. Domestic courts, by contrast, constitute facts on the ground. The common-law courts in particular have rich as well as lengthy histories. Accordingly, it seems unrealistic to talk about reforming domestic courts as a means of limiting their ability to resort to international law. Rather, more subtle issues of cultural norms and prestige arise.

In the United States, discussion of the role of international law in domestic adjudication often involves one of two categorical claims, each of which I wish to criticize. First, some authorities have suggested that foreign sources of law, including international law, should have no role in the shaping of judicial determinations of domestic law.³⁷

At the opposite extreme, some scholars have argued that foreign sources should enjoy a privileged status, in the sense that their “otherness” itself strengthens the case for their respectful assimilation.³⁸ I believe that both these claims display a lack of appreciation of the multiple functions of precedent and authority in the common law process.

A judge might look to outside experiences for various reasons. On occasion, local law itself refers to foreign law, whether due to conventional choice-of-law rules or the application of a doctrine that involves some comparative assessment (such as the forum non conveniens doctrine used to dismiss lawsuits that would benefit from being brought in another jurisdiction). Alternatively, judges might seek evidence of the instrumental effects of a particular rule and look at the experience of other jurisdictions as an empirical test. Similarly, judges might look to other sources to expand their conceptual apparatus. Finally, a judge might apply foreign law out of an independent sense of obligation. Unless one wishes to defend judicial ignorance and narrow-mindedness, only the last function raises any difficulties.

On the one hand, those who attack any use of foreign or international law in the common law process are guilty of confusing these different functions and thereby weaken the force of their arguments. On the other hand, those who argue for privileging this category of law have tended to collapse these functions exactly because some seem obviously appealing, thus obscuring the need to defend the more difficult one. In the United States, neither the critics nor the apologists have sufficiently explored the specific issues surrounding the positing of a foreign-source obligation to apply foreign law.

One argument that I note in order to disregard it is the claim that the privileging of foreign and international authority masks a substantive agenda, namely the importation of bien-pensant social-democratic values.³⁹

It may be true that some advocates of the privileging position fail to explain why the decisions of, for example, the Strasbourg court should count but the law and practices of non-European states do not.⁴⁰ Behind this failure may lie undefended normative preferences. However, the more persuasive advocates of using foreign and international law acknowledge the point and mount a general defense of their position.⁴¹ It is this general defense that I wish to address.

The basic argument for giving authoritative effect to international law rests on conformity and safety in numbers. A judicial consensus that crosses national boundaries, so the argument goes, matters more than a split of legal authority. To maximize the deference judges qua judges get from society, they should stick together. Thus, a foreign decision—say, the conclusion by the Strasbourg court that the European Convention on Human Rights contains an implicit ban on the criminalization of sodomy—should influence the Supreme Court of the United States in deciding whether the U.S. fundamental law similarly has an unstated but effective limit on governmental power. Moreover, this influence should rest on grounds other than instrumental observations (civilization as we know it did not come to an end in Europe after the Strasbourg court reached its judgment) or conceptual innovation (the particular arguments used to construct an implicit rule from general language in a fundamental text).⁴²

Rather, other courts should follow the Strasbourg court because doing so enhances their authority as well as that of the European body.⁴³

How does this accretion of authority work? First, the appearance of consensus serves as a secondary source of persuasion. Doubters will be more reluctant to challenge widely held beliefs than those that are openly contested. Second, persons may feel some social pull toward conformity and away from deviance. Cooperation across courts thus builds social pressure.

Accepting that this dynamic exists and can bolster judicial authority, one can still question whether it should proceed unchecked. Judicial authority, one might believe, does not work as an end in itself. We want to empower judges to the extent that they will act in ways that make us better off than we would be if they did not act, but not otherwise. For lawyers, of course, this is a hard point to acknowledge, because at least some set of lawyers inevitably will benefit from any accretion of judicial power. Proponents and opponents of any particular move, whether litigators or judges, will grow more powerful from having their controversy gain salience and perhaps will enjoy material rewards as well. Academics will have more to discuss authoritatively. But if we can broaden our horizons to consider the welfare of society, surely we must acknowledge that judges, like other state actors, are capable of arbitrary exercises of power that may threaten liberty.

Checking the lawmaking capacity of judges is tricky, however, because the common law methodology constitutes a style of argument rather than a naked assertion of raw power. Recent proposals in the U.S. Congress to forbid judges from relying on foreign precedent strike me as silly. Judges “rely” on precedent both when they weave it into their arguments and when they act on the basis of their understanding of it, and only the former can be observed. The legislation, in effect, seeks to regulate how judges write opinions, not what they do. The gesture seems empty.

A deeper problem is categorical. Conventional common law methodology simply fills in gaps that legislative enactments can supersede. But constitutional interpretation—in Europe, this means interpretation of the Treaty of Rome and the Convention on Human Rights—operates independently of legislative enactments. Legislatures have no authority to direct courts on how to interpret or apply constitutions.⁴⁴

As a result, legislatures cannot override either interpretive strategies or outcomes as to constitutional questions, even where the courts rely on international law. To the extent that courts frame their decisions as constitutional interpretation, Congress in the United States, and national parliaments in Europe, cannot do anything about controversial decisions (involving, for example, the rights and privileges of sexual minorities or the scope of capital punishment) that may incorporate outside sources of authority.

Put aside the problem that, in at least some instances, judges can bring international law into their decisions in ways that displace national legislatures. Are the outcomes based on international law necessarily desirable? The “safety in numbers” argument has a certain appeal. Some regularities in international practice maximize welfare independent of their effect on judicial prestige and power. Justice Antonin Scalia, a leading opponent of the incorporation of international law into constitutional decision making, still argues that the interpretation of international treaties requires judges to take account of the understandings of the treaty parties, including those understandings expressed by courts in other countries.⁴⁵

A more formal way of putting the point is that some legal structures have built into them the possibility of network effects, and that efforts of judges to develop these effects can be defended without privileging judicial prerogatives as such.⁴⁶

In sum, two problems face any effort to limit judicial aggrandizement based on the promotion of international solidarity. First, the legislative process cannot plausibly regulate rhetorical moves, as distinguished from discrete outcomes, and also cannot respond to outcomes placed on a constitutional footing. Second, some international solidarity is good, but separating the desirable, network-effects instances from judicial opportunism is hard. No categorical or structural approach seems to work.

Checking of international lawmaking by domestic courts thus requires approaches that operate internally to the domestic legal culture, as opposed to the institutional-design approaches discussed in Section III with respect to international organs. That is to say, the judges must limit their own actions, because limits imposed from outside seem neither reliable nor plausible. Framed in this manner, the problem resembles that involving constitutional development: internalization by judges of certain norms becomes the only effective means of guarding against excesses.

Earlier I questioned whether internalized cultural norms alone can function as checks on international tribunals such as the ICC and the Strasbourg court. The points I raised—lack of cultural solidarity and internalized norms—do not apply to many of the domestic courts that many scholars have asked to contribute to international lawmaking. These bodies, and in particular the federal courts of the United States, operate against a powerful background of tradition and well-developed professional identity. It is not patently inconsistent, then, to expect internalized cultural norms to do some work in checking domestic courts, but to expect less with regard to international tribunals.

The process of internalizing skepticism about the reliance on international authority has several dimensions. Those who select judges—in the United States, the president and a majority of the Senate do this for the most influential members of the judiciary—may try to predict whether a candidate has such skepticism, although ex ante predictions of this kind are notoriously unreliable.⁴⁷

Leading figures in the judiciary—in the United States, this means first and foremost the members of the Supreme Court—might expound on the reasons for adopting a more skeptical posture. And those who interact publicly with the judiciary and play a role in shaping judicial reputations, particularly members of the scholarly community, might praise or condemn judges based on whether they display a critical perspective toward claims of foreign authority.

The praise of skepticism runs against a certain grain in the legal academy. Legal scholarship for the most part avoids the scientific method, which means that the expounding of nonfalsifiable claims incurs no costs. Partly for this reason, creativity and shock value count for more than usefulness. A predictable egotism and self-regard leads, if not ineluctably then frequently, to ambitious claims that require the suspension of skepticism. The current popularity for judicial participation in international lawmaking reflects these factors at least to some extent.

Academia contains other forces, however, that may push the debate in another direction. Normal competitive pressures ensure that no conventional wisdom remains unchallenged for long, and an increase in the salience of a position tends to lead to greater critical scrutiny. In the last few years, we have seen in the United States the beginning of a serious debate about the legitimacy and value of the incorporation of international law into domestic common law. Although some of the antagonists have held on to reductive and absolute positions, new scholarship has taken a more nuanced and sophisticated approach to the problem. In particular, the image of international law as a monolithic authority, as well as the portrayal of domestic incorporation as an all-or-nothing proposition, has been superseded by analytically rich accounts that recognize multiple dimensions of the problem.⁴⁸

One consequence of the increasing sophistication of the debate is the subversion of arguments based on the authority, as distinguished from the usefulness, of international law. To be sure, some scholars insist doggedly on the existence of a clear line of practice in which domestic courts consistently over the centuries have used a monolithic body of “international law” to shape municipal norms.⁴⁹

But a growing consensus about the complexity of the issue lightens this purported historical burden by demonstrating that earlier judicial practices, far from being canonical evidence of a general pattern, represent discrete responses to distinguishable problems. This necessary first step makes possible a shift in the terms of debate. We now can make normative judgments about the products of the common law process freed from false constraints based on authoritarian claims.⁵⁰

A move away from obligatory reliance on international law in favor of more nuanced and consequentialist discussions may have a salutary effect on the common law process. Judges (much like all people) sometimes seek to avoid the pain associated with difficult decisions by depicting themselves as compelled to reach a result. Arguments based on authority invite the actor to disregard the actor's intuitions about the action's consequences or the extent to which it will displease relevant audiences. Restricting the domain of authority increases the likelihood that the actor will take into account the implications of the action. So cautioned, the actor—in this case, common law judges—may hesitate more often before encroaching on liberty.